Firearm.



C. A. NELSON.

FIREARM.

APPLICATION FILED ocT. 15. 1913.

Patented D80. 2 8, 1915.

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dnlflrniwz WITNESSES Patented Dec. 28, 1915.

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c, A. NELSON. FIREARM.

APPLICATION FILED OCT. l5 1913- uws rol?, 7m/Mu. Mw,

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CHARLES A. NELSON, F UTICA, NEW YORK, ASSIGNOR TO SAVAGE ARMS COMPANY,

` 0F UTICA, NEW YORK, A. CORPORATION OF NEW YORK.

FIREARM.

Specification of Letters Patent.

Patented Dc. 28, 1915.

Application led October 15, 1913. Serial No. 795,231.

a citizen of the United States, residing at Utica, in the county of Oneida vand State of New York, have invented certain new and useful Improvements in Firearms, of which the following is a specification.

This invention relates to guns of the automatic type, that is to say, guns in which the operation.. of extracting the spent shell, cooking the. piece and introducing a fresh cartridge are accomplished through the recoil of the gun, and it has forl its object to provide a gun of this class with an improved means7 requiring no movable part,

for controlling the opening of the breechV upon explosion of the charge with a view to prevent dangerous release at the breech of the powder gases.

My invention is dependent upon the known circumstance that on explosion of a cartridge `the cylindrical wall of its shell expands; and it consists in providing the cartridge chamber of the gun with a novel means for setting up resistance to the backward movement of the shell upon the explosion of the cartridge 4and the consequent expansion of the shell.

l have illustrated my invention in the accompanying drawings, Figure 1 showing a gun, having my improvements, in longitudi- .nal vertical section; Fig. 2 showing the frame, the barrel, and breech-closing element, the breech part of the barrel appearing vpartly in section; Figs. 8 and 4 being enlarged vertical sectional views on the lines Aing forced bac and y--g/ of Fig. 2, respectively; and, Fig. 5 a view of the front end of the breechclosure when formed in furtherance of my invention.

In `the drawings, a is the frame; Y) the barrel xed in the barrel abutment c; d and e the rbreech-block and breech-bolt, respectively, of the breech-slide or breech-closing element; f the spring normally holding the breech-slide with its breech-bolt in' closing relation to the rearwardly open "cartridge chamber g provided in the'breech or rear end of the barrel, being therefore adapted, u on the breech slide beupon explosion of a cartridge in the( breechto a limit afi l:torded by contact of the block at h with the barrel abutment, to return the breech slide in the usual way; i 1s the ring pin,

housed in the bolt and normally: pressed forward therein so as to protrude and impinge upon the cartridge by the springdriver j; 7c the Sear fulcrumed at Z between its ends and held with its rear end in dogging relation to the firing pin by the spring device fm; n the trigger and 0 the trigger pawl for transmitting to-the sear the Sear releasing movement of the trigger.

Describing that species 'of my invention shown in the drawings, the cartridge chainber g, which appears in Fig. 2 as extending from the abutment 'shoulder p for the forward edge of the cartridge-shell'rearwardly to the breech end of the barrel has a cartridge-shell-gripping surface-portion extending around its longitudinal axis that lis provided with laterally facing shoulders--in the present case, afforded by spiral ribs, corrugations or scorings g-and presentsan approximately straight profile in any section of said surface-portion that is substantially parallel with said shoulders. Upon explosion of a cartridge in a chamber thus formed (it -being assumed thaty thecartridge is related to the scored surface-portion of the chamber with substantially the same snugness of fit as it would be if said surface-portion were that of a cylinder represented by the inner apices of the scorings) and consequent expansion of the cylindrical wall of the shell against the scorings, re-

sista-nce to the rearward movement of the shell of a dual character is set up. Thus, first, there is the resistance due to the expansion of the shell outwardly against the scorings, and hence into more 'or less extended contact with the laterally facing shoulders they afford, and lasting only so long as the instant that thepressure 1s effective to maintainf such expansion (that is to say, assuming that the shell will contract upon cessation of the pressure sufficiently to practically eliminate the friction between the shell and the chamber, as it usually will, it being understood that if it did not contract so` as to eliminate friction between it and the chamber, such resistance, though reduced, `would last until the shell rearwardly cleared the chamber) and, second, there is also the resistance afforded by the fact that the shoulders are spiral and that the relatively forward one in each instance therefore more or less obstructs the rearward movement of the shell, this resistance llv usually lasting after the pressure ceases to act on the shell, that is, lasting until the shell rearwardly clears the shoulders. Thoughtboth of these forms of resistance exist in that adaptation of my invention herein shown, `it will be understood that either may be resorted to without the other.

After the pressure has expended itself the force, operative to drive the shell and hence the breech-block to the rearward limit (fully opening the breech) is the unexpended energy or force of recoil left stored in the shell and breech-closing element.

Where the scorings are so formed as to require rotary movement of theshell in order to clear the chamber rearwardly, resistance to such rotary movement of -the shell may be set up (thus urther opposing its rearward movement) by forming the breech-closing element with impress-forming means. rlhns the breech-bolt e is shown as provided with the radial scorings s on its acting face, the eifect of which will be to produce impresses in the rear face of the cartridge shell, the shoulder forming one side on each scoring and the coacti-ng surface of the corresponding impress coactf ing with each other to resist rotation of the shell (Fig. 5). Y

The smooth surface portion r'serves, in coperation with the portion of the shell embraced thereby, to form a seal preventing the backward release of the powder gases through the channels or Agrooves formed between the scorings.

Having thus fully described my invention, what l claim as new and desire to secure by Letters Patent is .1. A gun of the blow-back type including, with a cartridge-chamber-forming structure havlng its chamber open rearwardly, a chamber-closing element movable rearwardly in response to explosion-pressure to open said chamber, said chamber having means to resist .the backward movement of the cartridge on explosion and .thereby delay the backward movement of said element conslsting in a cartridge-shell-gripping surface-portion extending around the longitudinal axis of said chamber and provided with a laterally facing shoulder or shoulders and presenting an approximately straight p role in any section of said surface-portion that is parallel with said shoulder or shoulders.

2. A gun of the blow-back type including, with a cartridge-chamber-formng structure having its chamber open rearwardly', a

chamber-closing element movable rearwardly in response to explosion-pressure to open saidl chamber, said chamber having means to resist Athevbackward movement of the cartridge on explosion and thereby delay the backward movement@ of said element consisting in a cartridge-shell-gripping surface-portion 'extending around thev longitudinal axis-of said` chamber and provided with a spiralklaterally facing shoulder or shoulders and presentingr an approximately straight profile in any-section of said surface-portion that is parallel with said shoulder or shoulders.

3. A gun of the blow-back type including, with a cartridge-chamberorming structure having its chamber open rearwardly, a chamber-closing element movable rearwardly in response to explosion-pressure -to open said chamber, said chamber having means to resist the backward movement of the cartridge-on explosion and thereb delay the backward movement of sai ment consisting in a cartridge-shell-gripping surface-portion extending around the elelongitudinal axis of said chamber and provided with a laterally facing shoulder or shoulders and presenting an approximately straight prole in any section of said surface-portion' that is parallel with said shoulder or shoulders, said chamber also havlng Vanother and smooth cartridge-shell-grip ping surface-portion coactive with a the shell to form a continuous seal.

4. An automatic gun including, witha cartridgechamber structure vhaving its chamber open rearwardly and formed with means to impart rotary movement to the cartridge shell upon rearward movementtherepart of of, a chamber-closing element having `means to obstruct such rotary movement of v the shell. r l

5; An automatic gun including, with a' cartridge-chamberf'orming structure having its chamber open rearwardly and' formed with means to impart rotaryy movement to the cartridge shell upon, rearward move#` los,

ment thereof, a chamber-'closing element having a crosswise shoulder or shoulders to interlock with shoulders on the rear face of the shell. 1

In testimony 'whereof I aiiix my signature in presence of two witnesses.

NELSON.

Witnesses: I a Y Jos. G. SLIKER', dos. A. DAVIS,l 

